Against this backdrop, it is easy to see why William Lamb, metallurgist and chief executive of Lucara, is selling Mothae. “Mothae has beautiful stones,” but the numbers don’t add up, says Mr Lamb. The chances of finding so-called “specials” — the big high-quality stones that fetch millions — are too small to make much difference to the low average price per tonne of rocks extracted. The company has written off $18m of the mine’s value so far.
